The present invention relates to enclosed electronic process control equipment, and more particularly to an intrinsically safe portable programmer for communicating with the electronic process control equipment without electrical connection between the two.
Level measurement systems are one type of electronic process control device. Level measurement systems, also known as time of flight ranging systems, determine the distance to a reflector or reflective surface (e.g. the level of a liquid held in a storage tank) by measuring how long after transmission of a burst of energy pulses, the echo is received. Such systems typically utilize ultrasonic pulses, pulse radar signals, or microwave energy signals. Level measurement systems find widespread application in many different types of process control applications in a wide variety of diverse applications, such as the petroleum industry and the food industry.
Industrial process control applications in hazardous environments, such as the petroleum industry, often require the electronic process control equipment to be installed as enclosed devices for safety reasons. Once installed, the enclosed devices are inaccessible even for purposes of routine maintenance, programming and calibration. To access the device, the industrial process or processes operating in the work space must be disabled and the area deemed declassified, and only then can the electronic process control equipment be opened for maintenance or reprogramming.
The programming, calibration, and/or configuration of such electronic process control equipment is often performed using an on-board keypad or control panel. The keypad is accessed by opening the device after the industrial process and work space have been disabled and declassified. It will be appreciated that while the keypad is a necessary component to provide the capability for configuring, calibrating, and re-programming the device, the keypad is a component which does add to the cost of the device. In the case of enclosed electronic process control devices in hazardous environments, the switches or pushbuttons for the keypad must be explosion proof which adds further to the cost of the electronic process control device. Furthermore, the declassifying operation for a hazardous area is both time consuming and costly.
Accordingly, there remains a need for an apparatus which would facilitate the programming of enclosed electronic process control devices in a hazardous area.
The present invention provides an intrinsically safe portable or handheld programming device suitable for enclosed electronic process control equipment, such as level measurement devices.
In a first aspect, the present invention provides an intrinsically safe portable device for configuring the operation of electronic process control equipment, the electronic process control equipment includes a wireless communication receiver, the portable device comprises: (a) an enclosure; (b) an electronic circuit mounted in the enclosure; (c) a keypad coupled to the electronic circuit; (d) a wireless transmitter responsive to the electronic circuit and operative to transmit control signals to the wireless communication receiver on the electronic process control equipment for controlling the operation of the electronic process control equipment; (e) the electronic circuit includes a low voltage power supply and a low power microcontroller for operating at a low voltage level to eliminate the incidence of sparking.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.